Objective - （ ） To analyze the epidemiological characteristics of occupational noise induced deafness ONID （ ） diagnosed by Guangdong Province Hospital of Occupational Disease Prevention and Control GDHOD from 2016 to 2020 and - Methods the reasons non ONID diagnosis. The data of ONID patients diagnosed in GDHOD from 2016 to 2020 were collected “ from the Occupational Disease Report Card in the Occupational Disease and Occupational Health Information Monitoring ” “ ” - System subsystem of the China Disease Prevention and Control Information System . The data of non ONID subjects were ， collected from the occupational disease diagnosis archives in the same hospital and the relevant data were analyzed Results ， ， （ ） retrospectively. Of the 1 432 subjects 824 subjects were diagnosed as ONID patients mainly of mild ONID 86.0% . （M） ， M Male patients accounted for 88.0%. The median of diagnosis age was 45.0 years old and of length of employment of ， ， ， diagnosis was 8.3 years. ONID patients were mainly found in Zhongshan Dongguan Zhuhai Jiangmen and Guangzhou City in ， ， （ ） the Pearl River Delta accounting for 67.6%. The cases distributed in 519 enterprises mainly on manufacturing 90.2% . ， - ， ； Among the 139 enterprises each enterprise had 2 11 patients worked within five years accounting for 53.9% 91.1% of the -， - - - ONID patients were distributed in large medium and small enterprises. ONID patients mainly worked in non public enterprises that accounted for 91.3%. There were 606 subjects could not be diagnosed as ONID. The main reasons for not being （ ）， diagnosed were that the weighted value of better ear hearing threshold was less than 26 dB 34.8% the working history of （ ）， occupational noise exposure was less than three years 31.5% the weighted value of better ear hearing threshold was less thanConclusion 26 dB and the average hearing threshold of binaural high frequency was less than 40 dB 16.2% . The ONID ， ， -， - patients have the characteristics of group aggregation. The Pearl River Delta manufacturing industry large medium and - - ： small non public enterprises are the key points of ONID prevention. The main reasons for not being diagnosed as ONID were ， the working history of occupational noise exposure was less than three years the weighted value of better ear hearing threshold ， - was less than 26 dB and the average high frequency hearing threshold of both ears was less than 40 dB.