I find the reason. Because of timeout.When i set the timeout 5 seconds,it's ok. E:\window编程\网管资料\SNMP\SNMP4J\snmp4j_tool-1.8.1>snmp4j -v 2c -c public -p G ET -Ot -t 5000 192.168.14.155 1.3.6.1.4.1.28185.1.1.6.1 Table walk completed with status 0. Received 2160 rows. Table received in 3938 milliseconds.