Abstract: The flame-retardant finishing of traditional pad-dry-cure technology which caused loss to breaking strength on fabrics and the change of colour, influenced using on canvas.So a steam flame-retardant finish process has been studied.The influence of concentration of flame-retardant finish agent and catalyst, temperature of steaming on the effect of flame-retardant finishing,breaking strength and the change of colour was investigated.Using orthogonal analysis optimized process prescription and process conditions of the steam flame-retardant finishing.The experimental results revealed that compared with the traditional flame-retardant finish process，the fabric treated by this wet state process showed equivalent flame-retardant property but better breaking strength and other indexes.especially the color.The best technique were: flame-retardant finish agent CFR:350g/L,catalyst C52:40g/L, temperature of steaming 140℃,time of steaming 30min.

Key words: pure cotton canvas , steam flame-retardant finish , fabric property , orthogonal analysis