The invention relates to a preparation method for a high-solid-content low-viscosity polyacrylamide emulsion. According to the preparation method provided by the invention, a 30%-50% monomer aqueous solution is added into an oil phase system composed of an emulsifier, solvent oil and an azo initiator, a polymerization reaction is performed, the adding amount of a monomer is controlled to account for 20-30% of the total weight of the emulsion, the polymerization heat released in the preparation process is reduced, and the safety hazards are eliminated; and vacuum distillation is performed on the emulsion after polymerization is completed, the water content in the product is reduced, and the solid content of the product is improved. The polyacrylamide emulsion prepared by the preparation method reduces the viscosity and coagulation point of a high-solid-content emulsion product, solves the problems that the high-solid-content emulsion product has residues and accumulation in a medicine adding pump and a pipeline during field use, and finally the blocking is caused, and ensures that the field production is successively performed. The high-solid-content low-viscosity polyacrylamide emulsion product prepared by the method can be widely applied in various fields such as water treatment, papermaking and oil field mining.