Abstract: Because the first MG500 coal shearer of some mining corporation was limited by low fuselage and small volume,tank and oil pump couldn’t be installed on it and hydraulic pressure system only used emulsion liquid of coal face as power liquid.But components of the system couldn’t be suitable for emulsion liquid system and coal shearer often took place faults such as braking device contracted brake,coal shearer couldn’t move and so on.Aiming at the problems,the paper proposed a reformation scheme of braking device for hydraulic pressure system of the coal shearer,which used common components of hydraulic support to instead of primary imported components so as to make it to be suitable for emulsion liquid system.The actual application result showed the reformed coal shearer runs stably and reliably,faults rate is reduced greatly and maintenance is easy.