Antenna pattern 1S the best reflect10g of antenna's performance. There are many methods to measure the pattern of phased array antenna ,such as the technique of p1ane scanmng 10 near fie1d , focus1Og method in Fresne1 zone , genera1 method in far fie1d , etc. 1n this paper , the princip1e base and the rea1izatlOn method of the phased array antenna pattern's measurement with focus1Og method in Fresne1 zone are discussed. The patterns of near fie1d and far fie1d are compared through expenment. Considering the fact ,an expenment 1S made on the test10g error caused by distance error and frequency drift. The results indicate that this method to momtor the phased array antenna 's performance in Fresne1 zone 1S an effective method.