The invention discloses a super-long super slow release type polycarboxylic acid 
slump-retaining agent master batch suitable for projects such as hydraulic tunnels, railway tunnels, metros and underground oil and gas delivery adopting concrete having the capability of retaining 
slump for 4-6 hours under the conditions of 
hot weather and long distance. Limited by 40% of the 
mass percent of mother liquid, the total 
mass of synthesized raw materials is 1000 parts, the usage amount proportion is that the usage amount of polyether 
macromonomer accounts for 325-335 parts, the usage amount of unsaturated 
carboxylic acid micro-
monomer accounts for 10.0-18.0 parts, the usage amount of acrylic hydroxyalkanoate accounts for 35.0-45.0 parts, the usage amount of crosslinking 
monomer accounts for 5.0-10.0 parts, the usage amount of 
sulfonic acid type 
chain transfer agent accounts for 2.0-5.0 parts, the usage amount of 
hydrogen peroxide accounts for 2.0-3.5 parts, the usage amount of 
vitamin C accounts for 0.60-0.90 part, the usage amount of caustic soda liquid accounts for 7-10 parts, and the balance is water. The polycarboxylic acid 
slump-retaining agent is moderate in molecular weight, can be independently used or compounded with other polycarboxylic 
acid water reducing agents for usage, can remarkably improve the indexes such as slump-retaining property, cohesiveness and flowing retention ability of newly mixed concrete in 6 hours.