1. Huawei Technologies
Now the world's second-largest provider of telecom equipment-thanks in part to its success in the Indian market-China's largest telecom company is at the forefront of the latest 4G mobile-phone technology. Top 50: No. 5 
The battery giant's cutting-edge technology-notably its lithium-ion ferrous phosphate battery-makes the Shenzhen-based company a front-runner in the race to make mass-market electric cars. After marketing the first plug-in hybrid, BYD now expects to bring its all-electric E6 to market this year. Top 50: 16 
Taobao, Alibaba's consumer arm, has more than 145 million registered members--that's 43% of China's Web users. In 2010, Taobao plans to expand its empire by launching a Taiwan-specific online mall. Top 50: No. 29 
4. Huayi Brothers
In October, Huayi Brothers Media Group joined ChiNext, becoming the first film and TV company in China to list on any stock exchange. On opening day, the company's stock rose 148%, putting the value of the production house at more than $1.5 billion. Huayi Brothers, which also manages some of the country's top talent, is partnering with Disney on Disney High School Musical: China, due later this year. Top 50: No. 42 
China's largest Internet company by market value, Tencent first became a household name for QQ, its instant-messaging software. It then leveraged its brand name to branch into gaming and online dating , helping it rack up its member count to 450 million--more than either Microsoft's or Skype's messaging service in China. It ranks No. 5 in the world for the total hours spent on a Web site, and is the Chinese market leader in online games, with a booming market in virtual goods that helped boost third-quarter profits 93% year over year.
6. Suntech Power
Suntech's revolutionary Pluto technology decreases reflectivity of cells, ensuring that more sunlight is absorbed and increasing output to record-breaking levels. Its solar photovoltaic cells have a conversion efficiency of up to 19%, versus the industry average of 13%. This summer, Suntech is scheduled to open a plant in Arizona, becoming the first Chinese clean-tech company to bring manufacturing jobs to the U.S.
In November, Sohu's Sogou search engine released a new input method editor that speeds up searches for Chinese speakers. Based on cloud technology, it lets users type search terms in Pinyin (the Romanization of Chinese) instead of laboriously entering Chinese characters. The accuracy rate for conversion is 90%. Sohu also pledged to remove pirated video content from its site and set up a fund to buy licenses for Hollywood movies and TV shows.
Since its start in 2006, Eno has become a go-to shopping destination for Chinese teens and a design outlet for Chinese artists (it's one of the few online stores that sell local designs). The company has been so successful in reaching the youth market that it recently launched a consulting firm to help companies such as Coca-Cola, New Balance, Kraft, Unilever, and Ticketmaster do the same.
China's leading online travel-services company caters to the country's rapidly expanding middle class as well as executives of foreign companies pursuing Chinese business. Coca-Cola, Panasonic, Sony, and Baidu have all tapped Ctrip's savvy corporate-travel program to track employee trips and save renmimbi. Revenue for 2009 was $291 million, up 34% from the previous year.
The search giant lost clients in its transition to a new advertising system, Phoenix Nest, which lets clients track the effectiveness of their ads more closely than before and differentiates paid ads from authentic search results. (The company had been criticized for mixing the two.) Baidu should continue to dominate search in China, even if Google remains active there. Innovation All-stars