High water-absorbent polyacrylates could be prepared by concentrated aqueous solution polymerization within a short time period, heating the monomer mixture by water bath. The influences of initiator content, bath temperature, crosslinker content (Cc), and degree of neutralization on water absorbency (Q) were investigated. The temperature changing of the monomer mixture during polymerization was thoroughly analyzed. The increase of initiator content as well as the increase of bath temperature results in the increase of water absorbency and reduces the crosslinking efficiency. The results are in conformity with Flory＇s network theory and also illustrate that lower crosslinking efficiency occurs when the polymerization rate is faster. An empirical relation of Q = 1.40 Cc(-0.665) is obtained and its exponent is very close to -0.6 in a derived relation.