Objective To explore the relationship of hepatitis B virus surface antigen(HBsAg)infec-tion and family history of hepatocellular carcinoma(HCC)with age at primary liver cancer. Methods Totally 1 359 cases of primary liver cancer were enrolled. Their data of sex,HBsAg status and family history informa-tions of liver cancer were analyzed on the associations with diagnosis age. Results Of the 1 359 cases,1 053 were males and 306 were females,their average age at diagnosis was(54. 02 ± 10. 47)years(20-84 years). For HBsAg positive cases,the average age at diagnosis was 51. 99,significantly younger than that of HBsAg negative cases(61. 23),t = 13. 51,P = 0. 000. Cases with family history of HCC were diagnosed at a signifi-cantly earlier age than those without family history(52. 53 vs 55. 23,t = 4. 389,P = 0. 000). In HBsAg posi-tive cases,the average age at diagnosis showed a significant difference not only between males and females (51. 18 vs 54. 89,t = 5. 353,P = 0. 000),but also between cases with family history and cases without family history(51. 33 vs 52. 62,t = 2. 233,P = 0. 026). In HBsAg negative cases,the average age at diagnosis of males and females were 60. 83 and 62. 45 respectively(t = 1. 126,P = 0. 261). The average age at diagnosis of cases with family history and cases without family history were 59. 58 and 61. 92 respectively(t = 1. 728,P =0. 085),both showed no significant difference. Conclusion Cases of primary liver cancer with positive-HBsAg are diagnosed averagely 9. 24 years younger than those with negative-HBsAg in Qidong. Sex and family history of HCC significantly advance hepatocarcinogenesis only in HBsAg positive individuals,not in HBsAg negative individuals.