Based on the Spin Flip Model (SFM), vectorial chaotic synchronization characteristics of vertical-cavity surface-emitting semiconductor lasers (VCSELs) with isotropic optical feedback is numerically investigated. The results are as follows. First, when the external cavity round-trip time equals the propagation time of light from the transmitter to the receiver, both the x-linear polarization (LP) mode and the y-LP mode can realize very high complete synchronization. Second, when external cavity round-trip time is not equal to the propagation time and μ is near the lasing threshold, the better completely synchronized quality of the dominant y-LP mode can be temporarily achieved. In comparison, the governing x-LP mode can only realized poor synchronization quality. In addition, with the system governed by the mixed LP modes, each LP mode can obtain inferior synchronization quality. However, with injection current much greater than the threshold current, the completely governed y-LP mode can steadily achieve the best chaotic synchronization quality. At last, each LP mode of the injection can achieve good injection-locking synchronization with that of the receiver. While each dominant LP mode can obtaine poorer injection-locking synchronization quality than the corresponding suppressed LP mode, with equal power, two LP modes both can achieve almost identical high injection-locking synchronization quality. Namely, the LP state with less power can be obtain better injection-locking synchronization.