Objective To understand the epidemiological characteristics and influencing factors of imported severe malaria cases in Zhejiang Province. Methods The epidemiological data of imported severe malaria cases in Zhejiang Province from 2012 to 2020 were collected. SPSS 20.0 software was used to analyze the species of Plasmodium, distribution of cases, countries source of infection, interval time from disease onset to diagnosis were analyzed. Multivariate logistic regression analysis was conducted to analyze factors affecting severe malaria. Results A total of 127 severe malaria cases were reported in Zhejiang Province from 2012 to 2020, all were imported from abroad. Of them, 107 were infected with Plasmodium falciparum (84.25%), 11 with P. vivax (8.66%), 7 with P. ovale (5.51%), and 2 with mixed infection (1.57%). The severe malaria cases were distributed in 11 cities of Zhejiang Province, with the top 3 cities with the percentage to total reported cases being Taizhou (17.65%, 24/136), Ningbo (13.45%, 16/119) and Wenzhou (11.64%, 22/189). The number of severe cases in January, October and December accounted for more than 10% of the total reported cases, respectively. Among the 127 cases, 116 were males and 11 were females, and the mala/female ratio was 10.55 : 1, mainly occurred in the age of 30-59 years (98 cases, 77.17%), and among workers and businessmen. There were 9 foreigner cases, and 2 deaths occurred in 2013 and 2016. The source place of infection showed that 93.70% of the severe cases were imported from African countries, with top countries of Nigeria (35, 27.56%), Equatorial Guinea (13, 10.24%) and Democratic Republic of Congo (11, 8.66%). The time interval from initial diagnosis to diagnosis of severe malaria was longer than that of non-severe malaria cases (Z = -3.285, P < 0.05). Age (OR = 1.022, 95%CI: 1.004-1.041) and the time interval from initial diagnosis to diagnosis (OR = 1.046, 95%CI: 1.004-1.089) were the risk factors for severe disease. Foreign nationality (OR = 0.488, 95%CI: 0.241-0.990) and previous history of malaria (OR = 0.598, 95%CI: 0.399-0.895) had less chance causing severe malaria. Conclusion Imported severe malaria cases in Zhejiang Province are distributed in Hangzhou, Taizhou, Wenzhou and other cities. Most of them are males, aged 30-59 years, among workers and businessmen. The severe cases were mainly imported from Africa. Age and the time interval between first diagnosis and diagnosis are risk factors leading to severe malaria.