Theory and method research of equipment measurability is very important for improving the metrology support ability of equipment. Aiming at the lack of equipment measurability model inland, the multi-signal model method is presented for the measurability analysis and design. The basic theory of the measurability multi-signal model was summarized systematically, the optimum seeking method of the out-of-tolerance detection and position，and the design method of measure strategy were introduced in detail on the single out-of-tolerance assumption, without considering component reliability, measurement time and cost implications. The multi-signal model of self developed signal produce system was established, the correlation matrix was given and the verification tree was analyzed. The conclusions agree with the actual verification method of signal produce system, which proves that the measure strategy is reasonable and effective. 