Abstract: In view of the engineering problems of fast attenuation of anchor cable prestress and poor support stability in soft rock roadway，taking the shallow buried soft rock roadway in Hongshaliang Mine as the engineering background，the method of combining theoretical analysis with field industrial test is used to systematically carry out the research on the mechanism and prevention and control technology of anchor ca⁃ ble prestress loss. The results show that the prestress loss of anchor cable in soft rock roadway is affected by the coupling of multiple factors such as anchor cable material，tensioning equipment，construction technolo⁃ gy，surrounding rock creep and water environment change. The whole process can be divided into three stag⁃ es of rapid decline，steady decline and basically stable. Based on the loss mechanism，comprehensive pre⁃ vention and control measures such as replacing low-relaxation grouting anchor cables，calibrating tension⁃ ing tools，secondary compensation tensioning，and surrounding rock grouting reinforcement are proposed. The field test shows that the average loss rate of prestress of grouting anchor cable is reduced by 24.30% compared with that of ordinary anchor cable. The aging of the tensioning machine will increase the prestress loss rate by 32.37%. Regular calibration can effectively avoid the influence of equipment loss. The average prestress compensation rate of the secondary tensioning process of the anchor cable can reach 27.51%. The whole set of control measures can significantly inhibit the prestress loss of anchor cable in soft rock road⁃way，improve the coupling effect of surrounding rock support，and ensure the stability of surrounding rock of roadway. The research results can provide engineering reference for anchor cable support optimization and prestress loss prevention and control in similar soft rock mines.

Key words: soft rock roadway, grouting anchor, prestress loss, creep, surrounding rock supporting