By using KTP crystal as intracavity frequency doubling generator of a mode-locked Nd:YAP laser, efficient SHG in colliding pulse mode-locked (CPM) unstable resonator with antiresonant ring (ARR) and confocal unstable resonator has been demonstrated. The energy conversion efficiencies are 53.4% and 60.2%, pulse durations in fundamental wave are 8 ps and 18 ps, and the maximum energy fluctuation in second harmonic wave are 10.6% and 12.5%, respectively. The characteristics in both resonators and their experimental results are theoretically analyzed.