Objective To observe the correlation between long-term chronic pharyngitis and rheumatic heart vavular disease (RHD) caused by to long-term latent chronic rheumatic activity and to understand the progressive course of rheumatic heart vavular disease. Methods In 1126 cases with chronic pharyngitis, 319 cases with serum antistreptolysin O (ASO) level between 400-500 U/ml were followed-up. ASO, creatine kinase enzyme MB (CK-MB) and echocardiography were measured for follow-up since 1986. Of the 319 cases, 158 were male and 161 were female with the average age of 29.4 years old. By the end of 2009, 6 cases were lost during follow up, data of 313 cases including 155 male patients and 158 female patients whose average age was 49.6 were analyzed. As the number of every kind of rheumatic heart vavular lesion was so fewer for statistical analysis that the data were only listed in tables. The student's t test was performed to compare of the ASO, CK-MB between the group with vavular lesionss and the group without vavular lesion. Results ①Of the 313 cases, 9 cases suffered from rheumatic fever at the fourth year since 1986, and 29 cases had rheumatic fever 1, 2 or 3 years after the ASOs decreased to lower than 400 U/ml and no one developed heart valvular lesion.②Two hundred and seventy-five cases whose ASO in the range of 400-500 U/ml but with normal CK-MB were found by the end of 5, 10, 15, 20 years, 9, 42, 65, 78 cases had developed heart vavular diseases respectively. ③ The levels of CK-MB in the heart valvular disease groups were significantly higher than those in the non-vavular disease group, while the levels of ASO were not. Conclusion Some of the cases suffering from long-term chronic pharyngitis can have high levels of ASO, but with normal CK-MB. These patients may have latent long-term chronic rheumatic activity and develop rheumatic heart valvular disease years later.