∵a2+b2+c2+d2-ab+cd=1,且ad-bc=1(1),∴a2+b2+c2+d2-ab+cd=ad-bc,∴2a2+2b2+2c2+2d2-2ab+2cd=2ad-2bc,∴(a-b)2+(c+d)2+(a-d)2+(b+c)2=0,∴a-b=c+d=a-d=b+c=0,∴a=b=d=-c(2),把(2)代入(1)得:a2+a2=1,∴a2= 1 2 ,∴abcd=a?a?(-a)?a=-a4=- 1 4 .故答案为:- 1 4 .