Objective:To understand the infection rate of Coronavirus Disease 2019 (COVID-19) in close contacts in Shandong province and explore the risk factors of infection.Methods:All data from close contacts of 2019 novel coronavirus (2019-nCoV) infected persons in Shandong province were collected for descriptive epidemiological analysis, and risk factors were analyzed by logistic regression.Results:Up to March 6, 2020, a total of 15 702 close contacts had been reported in Shandong province, of whom 321 cases were infected with 2019-nCoV, with an infection rate of 2.04%. Among all the factors, the top five with the highest infection rate were close relatives (13.39%), frequent contact (9.58%), working/living/studying in the same room (7.54%), two or more contact cases (4.58%), and over 60 years old (3.10%). Single-factor analysis showed that exposure to two or more cases, over 60 years old, close relatives with cases, frequent contact and working/living/studying in the same room were the risk factors for infection in close contacts. Multivariate analysis showed that exposure to two or more cases ( OR=2.510, 95% CI: 1.843-3.417), 30~60 year old group ( OR=1.513, 95% CI: 1.141-2.007), frequent exposure group ( OR=20.025, 95% CI: 14.625-27.419), working/living/learning in the same room ( OR=2.406, 95% CI: 1.385-4.182) and medical institution exposure ( OR=2.366, 95% CI: 1.149-4.871) were risk factors of infection in close contacts. Conclusions:Tracking and managing close contacts was an important measure to control the COVID-19 epidemic situation, and reducing crowd concentration, keeping a proper social distance and taking effective protection were effective measures to control 2019-nCoV infection.