The behaviors of platinum dissolution in N21 and N31 phosphate laser glass under different temperatures and oxygen bubbling conditions were investigated in this work. By measuring and comparing the optical absorption at 400 nm, the effects of oxygen gas flow rate, melting temperature, and processing time on dissolution rate of platinum in N21 and N31 laser glasses were examined. The relation between dynamic parameters of platinum dissolution (diffusion coefficient and activation energy) and melting conditions (melting temperature, processing time and oxygen gas flow rate) was disclosed. This provides important references for manufacturing platinum inclusion free neodymium laser glass used for high power laser.