Abstract: Abstract: Phenolic resin, epoxy resin, styrene butadiene rubber and polytetrafluoroethylene can be used as friction material matrix. Due to poor wear resistance, heat resistance and adhesive properties of epoxy resin, styrene butadiene rubber and polytetrafluoroethylene, their applications in friction materials are limited. The advantages of phenolic resin on the heat resistance, adhesive property, mechanical properties, processing properties and lower cost make it become the most commonly used in adhesive base material of composite friction material. However, the pure phenolic resins are brittle, poor toughness, high hardness, poor heat resistance, low strength and large noise during using stage, so modification is an effective method to improve the comprehensive performance.The effects of different ratio of boron modified phenolic resin (BPF) and nitrile butadiene rubber (NBR) on mechanical properties, thermal stability, friction and wear properties of the friction material were investigated. Filled with carbon fibers, steel fibers, graphite particles, Al2O3 particles and deposit BaSO4 particles, the friction material was prepared with different ratios of boron modified phenolic resin with NBR, which was used as the matrix material. The friction material was formed by die pressing in the temperature of 160℃ and in the load of 10 MPa. The density of the friction material was tested by DH-300 electronic densimeter, the hardness of the friction material was tested by XHR-150 plastic Rockwell hardness tester, the compression strength of the friction material was tested by CSS-44100 electronic universal material testing machine, and the friction and wear properties of the friction material was tested by M-2000A friction and wear testing machine in the loads of 100, 150 and 200 N. The thermal stability of the friction material was analyzed by SMZ1000 zoom stereo microscope. The results showed that the BPF/NBR ratio affected the mechanical properties, wear resistance and heat resistance of the friction material considerably. When BPF/NBR ratio was 6:1, the friction material has the highest density, hardness and compression strength，which are 1.933 g/cm3、105 HRL and 134 MPa respectively . When BPF/NBR ratio was 5:1, the friction material has the least wear lost. With the increasing of BPF/NBR ratio, the plowing resistance of the friction material was enhanced and the adhesive transfer was weakened. The thermal stability of the BPF was enhanced when modified again by NBR, and the best ratio was between 4:1 and 5:1.