The absorption characteristic is an important factor for laser machining. A laser absorption rate experimental platform of titanium alloy is established using the integrating sphere-photodiode system. A Quasi-Continuous-Wave (QCW) pulsed Nd: YAG laser is used as the laser source, operating at a repetition rate of 400 Hz and pulse duration of 200μs. The purpose of our study was to show the characteristic of QCW. Experimental results show that higher absorption efficiency is caused by higher peak power of the pulse, which would benefit for the performance of laser machining.