Abstract:Abstract : Research purposes : The second Hengqin Bridge is the longest - span highway steel tn^ss arch bridge With the span of ( 100 + 400 + 100) m. The bndge is featured witii novel appearance and advanced technology, which is concentrated on many disadvantageous factors of long - span, typhoon, earthquake and marneclimate. The paper researches its span arrangement,earthquake resistance system, anticorrosion system and construction methods,to provide engineerng experience and reference for the design of long - span steel truss arch bridge. Research conclusions: ( 1 ) Using steel - concrete mixed end poral pier, the side span of the brdge is shorten,the negative force of side bearng is eliminated,the whole brdge is located on straight line,the transition with the approach brdge is more smooth,which make the brdge more economical and more beautiful. (2) Viscous dampers are used in the main piers,and E - shaped steel dampers are used in side piers,to effectively improve the seismic peromiance of brdges. (3) The cold application zinc coatings system is first adopted in China,solving the problem of t!ie long - term anti - corrosion of steel bridge. (4) The big - tonnage longitudinal movable supports with a temporary locking devices are developed, the construction method without tie bar is adopted for the first time to ensure navigation durng the construction period .