Six reinforced concrete beams were constructed and tested to investigate the effectiveness of strengthening with prestressed carbon fiber reinforced polymer (CFRP) plates. One of the beams served as a control specimen, another was strengthened with nonprestressed CFRP plates, and the remaining four were strengthened with prestressed CFRP plates. A set of self-developed anchorage devices for CFRP plates were introduced in this program. Monotone static loading experiments was carried out, and comparisons are made between the control beam, the nonprestressed beam and the prestressed beams. The serviceability and the ultimate performance of the concrete beams were improved by strengthened with prestressed CFRP plates.