InAs/InGaAs digital alloy strain-compensated quantum well lasers have been grown on InP substrate by gas source molecular beam epitaxy. Multiple quantum wells composed of compressive InAs/In0.53Ga0.47As digital alloy triangular wells and tensile In0.43Ga0.57As barriers were used as the active region. X-ray diffraction measurements confirmed the pseudomorphic growth and high crystalline quality of the QW structures. The peak emission wavelength of the laser is 1.94μm at 100K under continuous-wave driving current of 130mA, and the threshold current density is 2.58kA/cm2. An unusual blue shift of the laser spectral with the increase of the temperature was found, which is originated from the reduced slope of maximum gain function, due to the relatively high internal absorption and weak optical confinement in the laser structure.