Abstract: ObjectiveVariation of latex physiological parameters of Hevea brasiliensis plants at different TPD extent were studied to provide theoretical references for early prediction of tapping panel dryness(TPD) and illumination of TPD mechanism in H. brasiliensis tree. MethodH. brasiliensis Reyan 7-33-97 plants at different TPD extents were used as the experimental materials. Variation of latex yield and contents of latex thiol,inorganic phosphorus,sucrose,crude enzyme liq-uid protein,Mg2+ and lutoid bursting index of plants at different extents TPD were determined. Correlation between variations and occurrence of TPD were analyzed. ResultWith increase of TPD extent, latex yield significantly decreased(P<0.05, the same below) while dry rubber content, sucrose content, Mg2+ content and lutoid bursting index went up. When TPD extent was at the highest level,the latex production reached the lowest level which was 13.56 mL per plant, Mg2+ content and lutoid bursting index were 41.57 mmol/L and 55.22%, respectively. When TPD extent increased, latex thiol, inorgan-ic phosphorus and pH value decreased. Latex thiol and inorganic phosphorus contents were significantly lower than those of healthy trees. There was no obvious change in terms of crude enzyme liquid protein content(P>0.05). ConclusionLatex thiol,inorganic phosphorus,Mg2+ and lutoid bursting index are closely related to TPD extent of H. brasiliensis, which can be considered as key indicators of early prediction of TPD.