In the coal gasification plant, high temperature and high pressure wear-resistant pumps ( such as black water circulating pump, quench water pump, lock hopper circulating pump, etc. ) have long been faced with serious wear and corrosion, short life of mechanical seals and low operational reliability. According to many years of engineering practice experience, this paper makes a systematic optimization study from the aspects of hydraulic model optimization, structural innovation design, material optimization and mechanical seal system upgrading, and applies the results to the technical transformation of coal gasification plant in Shenhua Ningxia coal indirect liquefaction project. The practice shows that the efficiency of the optimized pump is increased from 64 % to 74.5 %, the annual power saving is 270,000 kilowatt hours, the failure rate is reduced by 60 %, the service life is doubled, and the economic and social benefits are remarkable. It provides a useful reference for the performance improvement of pumps in similar harsh working conditions.