Changes in tissue structure, rheological properties and water content of raw and heated sea cucumber meat were studied. Sea cucumber Stichopus japonicus was heated at 25 ℃, 70 ℃ and 100 ℃ water for 5 min. The structural changes were observed using a light microscope and the rheological parameters (rupture strength, adhesive strength and deformation)determined using a texture meter. Microscopic photograph revealed that the structural change of heated meat was greater than that of raw meat. The rupture strength, adhesive strength and deformation of raw meat were smaller than those of the heated meat. Meanwhile, rheological parameters showed positive correlation with heating temperature. These changes are mainly caused by thermal denaturation and gelatinization of collagen during heating. These changes were also evidenced in observations using a light microscope and differential scanning calorimetry.