Magnetic nanoparticles (MNPs) used for magnetic hyperthermia can not only damage tumor cells after elevating to a specific temperature but also provide the temperature required for thermosensitive liposomes (TSL) to release doxorubicin (DOX). MNPs injected into tumor will generate heat under an alternating magnetic field, so the MNPs distribution can determine temperature distribution and further affect the DOX concentration used for tumor therapy. This study proposes an asynchronous injection strategy for this combination therapy in order to improve the DOX concentration value for drug therapy, in which the MNPs are injected into tumor after a certain lagging of TSL injection in order to increase the TSL concentration inside tumor. In addition, the evaluation of treatment effect for this combination therapy is implemented by considering two different MNPs concentration distributions and two biological heat transfer models. The simulation results demonstrate that the treatment effect for combination therapy can be significantly improved after considering the proposed asynchronous injection strategy, which can mainly attribute to the improvement of DOX concentration. The DOX concentration difference during therapy is generally relevant to both the lagging time of different injections and the local temperature distribution due to MNPs concentration distribution.