By employing the Master Equation theory, the lasing properties of the quantum dot-microcavity coupling system were studied. For different types of coupling systems, i.e., “good system” and “more realistic system”, their lasing phenomenon under external pump field were investigated individually. Moreover, the influence of the detuning and the pure dephasing on internal characteristics of the coupling system, such as its second-order correlation function at zero time delay or the number of photons in cavities was analyzed. The numerical simulations show that, for a “good system”, when the detuning between a quantum dot and a cavity is not very large, the certain pure dephasing can improve the lasing properties of the coupled system; for a “more realistic system”, due to the difficulty of photon gathering in a cavity under off-resonant conditions, it is very hard to observe the lasing phenomenon. However, the pure dephasing will still play an important role on modulating the light field and the photon numbers in the cavity. These results may play positive effects on some research either on lasing with the single quantum dot, or modulating the interaction between light and matter etc.