Abstract: The experiment aimed to study the difference on the dietary nutrient digestibility of different genetic basis beef cattle during two nutrient levels.Forty-eight heads of different genetic basis beef cattle （Charolais×Simmental-crossbred cattle,Gelbvieh×Simmental-crossbred cattle,Angus×Simmental-crossbred cattle and Limousin×Simmental-crossbred cattle) were introduced，feeding two different nutritional level of diets，adopting 4×2 two factor design，and carrying on the seven days of digestion experiment using endogeny indicator method.The results showed as follows：①From genetic basis，crude protein digestibility in Gelbvieh×Simmental-crossbred cattle was significantly higher than that in Angus×Simmental-crossbred cattle (P＜0.05)，and extremely significantly higher than that in Limousin×Simmental-crossbred cattle（P<0.01）, crude fat digestibility in Gelbvieh×Simmental-crossbred cattle was extremely significantly higher than that in Charolais×Simmental-crossbred cattle and Angus×Simmental-crossbred cattle (P＜0.01).②From nutritional level，the nutrient digestibility of beef cattle in feeding a high nutrition diet were extremely significantly higher than that in feeding a low nutrition diet (P＜0.01).③From the interaction of genetic basis and nutritional level，nutrient digestibility decreased with the increase of nutritional level of diet in Charolais×Simmental-crossbred cattle,Angus×Simmental-crossbred cattle and Limousin×Simmental-crossbred cattle，while Gelbvieh×Simmental-crossbred cattle were on the contrary.The results indicated that genetic basis had significant influences on crude protein digestibility and crude fat digestibility （P＜0.05），nutritional level of diet had significant influences on the digestibility of dry matter，organic matter，crude protein，crude fiber，crude ash and crude fat （P＜0.05），crude protein digestibility were influenced significantly by genetic basis and nutritional level of diet at the same time （P＜0.05）.

Key words: genetic basis; nutritional level; interaction; digestibility