Abstract: Various high aspect ratio microstructures were prepared on the basis of UV-LIGA technique by using a new type of SU-8 photoresist. The influences of heat treatment and exposure on high aspect ratio microstructures are mainly discussed. The cracking and collapse of microstructures are favorably solved. Based on a series of contrast experiments, the SU-8 process is optimized and the highest aspect ratio of microstructures with 27:1 is successfully obtained.