To increase the carrying capacity of hydrostatic extrusion cylinder, sleeve structure was used to offer pre-stress on the inner cylinder by heat interference fit. The stress distribution along the thickness and relationship between thickness combinations and interference gap were studied by finite element method during design of sleeve structure applied in hydrostatic extrusion cylinder. The results show that, for any thickness combinations, as the interference gap increased, the maximum value of equivalent stress first increased and then decreased. The maximum value of equivalent stress located at the inner surface for both inner cylinder and outer cylinder, and as the thickness of inner cylinder increased, the value of equivalent stress at inner surface of inner cylinder increased and that at the inner surface of outer cylinder decreased. In the circle direction sleeve structure leads to compressive stress on the inner cylinder and tensile stress on the outer cylinder. After full loading for inner cylinder, tensile stress caused by internal pressure in the circle direction was offset by pre-stress. When the interference gap and thickness of inner cylinder were 0�15 mm and 35 mm respectively, the value of equivalent stress at inner surface of both inner cylinder and outer cylinder were the same and lowest.%为了提高静液挤压筒的承载能力，采用组合筒热套装结构对内筒施加预紧力，并采用有限元分析的方法对组合筒（内筒内径80 mm，外筒外径290 mm）套装尺寸与套装过盈间隙的匹配关系进行详细分析，研究了不同内筒与外筒壁厚组合与套装过盈间隙之间的关系，给出了应力沿组合筒壁厚方向分布的情况。结果表明：对于不同内筒与外筒的壁厚组合，等效应力的最大值都是随着过盈量的增加，先降低后升高；无论是内筒还是外筒，等效应力均在内壁处最大，随着内筒壁厚的增加，内筒内壁的等效应力逐渐提高，外筒内壁的等效应力逐渐降低；热套装后内筒环向受压应力，外筒环向受拉应力；承载后，内筒处由内压引起的环向拉应力被套装过程产生的环向压应力所抵消；当套装过盈间隙为0�15 mm，内筒壁厚为35 mm时，内筒内壁和外筒内壁等效应力数值基本一致，等效应力最低。
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