To the problem of several radars tracking several targets in ballistic missile defense, the cooperative detection task programming of multi sensor is investigated. Several chronological detection tasks are derived according to forecasted trajectories of targets. In each task, the optimal resource assignment of multi sensor is described by a 0-1 integer programming program. A cooperative detection scheme is obtained by solving all the problems. The constraints of detection capability and cooperative detection modes are observed. The task programming is demonstrated based on a hypothetical scenario of ballistic missile defense. The rational cooperative detection schemes are programmed. And several targets are tracked continuously and stably at various cooperative detection modes.