* Shanghai stocks higher, blue-chip CSI300 index up
* Gains in Shanghai stocks led by Guodian Nanjing Automation Co Ltd and losses by Cultural Investment Holdings Co Ltd
* China's A-shares are at 26.1 percent premium over H-shares
SHANGHAI, March 20 (Reuters) - China stocks erased early losses to end higher on Tuesday, led by healthcare companies, and as Beijing pledges further market opening as talk of trade war mounts.
** At the close, the Shanghai Composite index was up 0.3 percent at 3,290.64, while the blue-chip CSI300 index was up 0.08 percent at 4,077.70.
** The smaller Shenzhen index ended up 0.23 percent and the start-up board ChiNext Composite index was higher by 1.18 percent.
** China will open up its economy further, and its door to the outside will only get wider, with foreign and domestic firms allowed to compete on an equal footing, Premier Li Keqiang said at the close the country's annual parliament session on Tuesday.
** The familiar-sounding pledges from Beijing came as the prospect of a global trade war loomed in the wake of the United States' imposition of hefty import tariffs on steel and aluminium earlier this month.
** An index tracking major healthcare firms extended climb to a record high, having gained over 10 percent this year, as traders and analysts expect the healthcare industry to benefit from Beijing's reforms and the country's consumption upgrade in the sector.
** "The government revamp will help promote the long-term development of the healthcare and pharmaceuticals industry," Soochow Securities wrote in a report, noting investors could pay close attention to the investment opportunities in innovative drugs and high-end generic drugs.
** The view was echoed by many other domestic brokerage firms who also expressed similar optimism for the industry.
** Around the region, MSCI's Asia ex-Japan stock index was firmer by 0.15 percent, while Japan's Nikkei index closed down 0.47 percent.
** At 07:09 GMT, the yuan was quoted at 6.3301 per U.S. dollar, 0.01 percent firmer than the previous close of 6.3308.
** The largest percentage gainers in the main Shanghai Composite index were Guodian Nanjing Automation Co Ltd up 10.1 percent, followed by Chongqing Iron & Steel Co Ltd gaining 10.04 percent and Guizhou Yibai Pharmaceutical Co Ltd up by 10.03 percent.
** The largest percentage losses in the Shanghai index were Cultural Investment Holdings Co Ltd down 8.27 percent, followed by Tonghua Grape Wine Co Ltd losing 6.56 percent and Xining Special Steel Co Ltd down by 6.49 percent.
** As of 07:10 GMT, China's A-shares were trading at a premium of 26.14 percent over the Hong Kong-listed H-shares. (Reporting by Shanghai Newsroom; Editing by Subhranshu Sahu)