In this study, a carbon-fiber-reinforced composite packaged fiber Bragg grating (CFRP-FBG) surface-bonded sensor is developed for strain and temperature monitoring of wind turbine blades. To address the limitations of bare or simply bonded fiber Bragg grating (FBG)—such as insufficient mechanical protection, reduced strain-transfer efficiency, and poor operational stability—the proposed sensor uses a carbon-fiber-reinforced composite (CFRP) encapsulation structure that matches the blade substrate material, improving mechanical compatibility and strain transfer. Static cantilever-beam experiments show that the CFRP-FBG sensor exhibits a strain sensitivity of approximately 1.22 pm/με with a linearity of 0.9998, and the measured strain agrees with theoretical calculations and strain-gauge results within 1–2%, corresponding to a strain-transfer efficiency above 98%. Temperature calibration from −60 to 60 °C demonstrates a sensitivity of 18.63 pm/K and strong wavelength–temperature linearity. The sensor was further installed at four key positions on an operating wind turbine blade. Dynamic monitoring results indicate that the measured strain histories correspond closely to blade rotational speed and cyclic loading, without noticeable drift or signal loss during continuous operation. These results demonstrate that the CFRP-FBG sensor provides high sensitivity and feasibility for online strain and temperature monitoring of wind turbine blades under representative operating conditions.