Abstract: In the light of the research on the technologies of the prestressed concrete beams with pretensioned bent-up tendons，eleven groups (33) of pull-out test specimens of strands were designed，whose pull-out tests were done， and the characteristics of bond slip，the bond strength，the failure mode of anchorage and the factors affecting the bond behavior of strands were analyzed and discussed in detail． The formula calculating the bond strength between strand and concrete was got，and the calculated results showed a good agreement to the test results． It showed that the results of the fomula was on the safe side twagh the comparison of the measured values．