Optical Fiber Bragg Grating (FBG) sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, especially fitting for measurement applications in harsh environment. A novel integration of FBG sensors into clothing is becoming an increasingly important segment in electronic textile research. A functioning prototype of such an intelligent biomedical clothing is introduced. It aims at the integration of optical fibers based sensors into functional textiles for extending the capabilities of wearable solutions for body temperature monitoring. According to the laws of human body physiology and heat transmission in fabric, the mechanism of heat transmission between body and clothed FBG sensors was studied and the calculating formula reflecting the heat transfer process between body and clothed FBG sensors was presented. Some details and overview regarding our ongoing efforts for achieving the goals are provided. The experimental results are in good agreement with those obtained by temperature-field simulation. This should favor their use for clinical axillary temperature monitoring.