The present study was performed to evaluate the effect of Tetracycline-HCI and Saline on the change of implant surface microstructure and surface roughness according to application time. Implants with resorbable blasting media surface were utilized. Before test all 13 implants were measured surface roughness. Among them, 6 implants were rubbed with 50mg/ml Tetracycline-HCl solution and other 6 implants with saline for $frac{1}{2}$min., 1min., $1frac{1}{2}$min., 2min., $2frac{1}{2}$min and 3min. Then, specimens were processed for scanning electron microscopic observation and surface roughness after test. The results of this study were as follows. 1. Control group showed a few irregular, rough, uneven surface with crater-like depression. 2. The test group with Tetracycline-HCl conditioning showed an altered surface when Tetracycline-HCl was applied for 30secs, and showed a various surface alteration as application times go on. 3. The test group with Saline conditioning showed no significant surface differences and surface roughness. 4. The significant increase of Ra value was showed when Tetracycline-HCl was applied for 30secs. In conclusion, the 50mg/ml Tetracycline-HCl must not be applied for the RBM surface implant for surface treatment.