The contestant of the 26th Chinese Physics Olympiad finals is asked to design and make a digital clinical thermometer based on the relationship between thermistor with negative temperature coefficient (NTC) and temperature in the experimental competition I. Then,in the experimental competition II,measurement of minimum deviation angle and refractive index and determination of dispersion curve and angular dispersion power of optical glass are the two main parts. The content,principle involved and some solutions are discussed,and the examination results are analyzed.