Abstract: The soil water content under intercropping land has inverse ratio to poplar space between rows(SBRs), i.e.it decrease 1.0% by adding 1m SBRs within 3～15m space bound, which shows that the intercropping could reduce water loss from soil to atmosphere. The wheat leaf chlorophyll content has the same relation with the SBRs, which indicates poplar shading on wheat can increase leaf chlorophyll content. The study, on the other hand, demonstrates that wheat photosynthesis rate and transpiration rate have direct ratio to SBRs, and they increase 1.3μmol/m²·s and 0.2μmol/m²·s by widening 1m space, respectively. The over small SBRs will lead photosynthesis rate to decrease, and to affect the wheat biomass and yield. The SBRs, in which the wheat could get the highest yield by equation forecast under 4 years old poplar stand, is 21～22m.