Recently, near-fundamental-frequency oscillations (NFFOs) have been observed in practical wind power integrated systems via MMC-HVDC (WISM). However, a practical WISM is often high-order, causing the oscillation risk assessment to be computationally heavy. Therefore, in this paper, an efficient stability criterion is proposed, which gives the critical stability conditions considering the impact of number of generators and network topology. Then NFFO risk of a WISM under different numbers of generators and network topologies can be quickly judged. The stability criterion can be obtained via the Nyquist-based stability analysis on a single generator integrated system via MMC-HVDC and hence is simple in application. In addition, derivations of the stability criterion also give an analytical explanation to the NFFO risk induced by the integration of wind power. Finally, effectiveness of the proposed method and conclusions drawn is verified based on a typical WISM.