Research conclusions：(1) Using the deck type steel braced arch at the No, 8 bridge site(416m) of the Hutaioxia Jinsha River Bridge is the best engineering plan. Using the steel truss suspension bridge at No. 27 bridge site (98 + 660 + 98 m) can remain the condition for the hydroelectric plan of river and can get the better economic and social benefits. The deck type steel braced arch has features of the good load bearing capacity, good rigidity and nice looking and is suitable for the high mountain and deep valley area，but it produces the impact on the water storage and shipping under bridge because the arch rib is installed on bottom of the structure. (3)The steel truss suspension bridge has the features of the fine anti - seismic performance and good rigidity to meet the train requirement. (4) The research result can provide the reference to the type selection of the large span railway bridge in mountain and deep valley area.