【Objective】To study the relationship of compression ratio between axial stress and castor seeds in different states with different squeeze methods. 【Method】Cold pressing tests of complete and crushed castor seeds were accomplished in different squeeze ways with different squeeze rates. Hyperbolic compression relationship model between ratio and stress was developed on the basis of the Kawakita’s equations. The parameters of the model were determined by the least square method according to the tested results.【Result and conclusion】 The results showed that crushed castor seeds achieved an equivalent compression ratio consistent with complete ones， while the actual compression ratio was much smaller than that of the complete seeds. Pressing repeatedly under the same conditions can achieve a greater compression ratio than that of a single press. Simulated values and measured values matched well by comparison of values and their error analysis.