Xinghuo 2 Well was located at the top point on Yakela hump in Shaya apophasis，and it was an important prospecting well. Borehole well was very instability because the open well was long，wellbore size was large，and the petrography character was complex in the second interval. After the electropositivity well drilling fluid system was applicanted，and corresponding measures of maintaining and hangling technics was taken，these down-hole troublesome condition was solved. It included that round trip was touchdown in upper formation and tight hole sticking occurred frequently in down formation. The wellbore was stability during the course of drilling. At last， the success of drilling the second interval laid the foundation for future work in Xinghuo 2 well.