Abstract: In the configuration of the fiber laser/amplifier, the characteristics of the fiber pump combiner influence directly on the output power of the laser/amplifier. According the basic structure of the fiber pump combiner, the origin of the loss was analysed, the characteristics of power and temperature in some series of domestic combiner were studied in different conditions. The influence on the working temperature of pump combiner at the factor of the loss of pump energy, the return of pump energy, the ambient temperature and the brightness of pump light was pointed out. Some new type high power combiner was tested and the result demonstrates one input fiber of the combiner can stand up over 100W pump power, which make it possible to create the kilowatt fiber laser based on all-domestic appliances. Some correlative results of this research can provide the reference of the design and the heat management for the fiber combiner.