In order to improve the success rate of Radio Frequency Identification (RFID) tag identification, automatic sorting efficiency and intelligent level of packaging production line, an automatic packaging, detection and distribution system is designed by combining RFID technology with the detection system of packaging production line as the research object. The RFID detection system is introduced, including tag, reader, antenna and control system. To solve the problem of tag collision in RFID identification, an improved ALOHA algorithm is proposed and the dynamic predictive weight is used to estimate the number of tags so that the number of tags is approximately equal to the length of the data frames. The validity of ALOHA algorithm is verified by experiments. Experimental results show that the average collision rate is only 1.1%, and the success rate of the whole system can reach 99.6%. The improved ALOHA algorithm can effectively avoid tag collision. The system can complete the inspection automatically with less time and higher accuracy. The designed inspection system can improve the inspection efficiency of packaging production line and has high market application value.