Social work supervision is an important mechanism for social work personnel training. Through the binary analysis framework of “leadership-subjectivity,” it can be found that the effectiveness of social work supervision in accomplishing the supervision tasks within a given time depends on the effectiveness of accompanying supervision characterized by co-situationality. Only by giving full play to the leadership of the social work supervisor and the subjectivity of the social worker and the shaping of the synergy between the two can the ideal effectiveness of accompanied supervision be realized. From the point of view of the working mechanism of accompanying supervision, only by means of the integration mechanism, guidance mechanism, participation mechanism, and cultivation mechanism can the supervisor accomplish the goal of supervising and cultivating social work effectively by fully activating and cultivating the subjectivity of the social workers while accomplishing the transformation from embeddedness to integration.