∵a是方程x 2-2002x+1=0的根,
∴将x=a代入方程得:a 2-2002a+1=0,
∴a 2-2002a=-1,a 2+1=2002a,
则2a 2-4003a+1+
2002
a 2 +1 =2(a 2-2002)+a+1+
2002
a 2 +1
=-2+a+1+
2002
2002a =-1+a+
1
a =-1+
a 2 +1
a =-1+2002=2001.
故答案为:2001
∵a是方程x 2-2002x+1=0的根,
∴将x=a代入方程得:a 2-2002a+1=0,
∴a 2-2002a=-1,a 2+1=2002a,
则2a 2-4003a+1+
2002
a 2 +1 =2(a 2-2002)+a+1+
2002
a 2 +1
=-2+a+1+
2002
2002a =-1+a+
1
a =-1+
a 2 +1
a =-1+2002=2001.
故答案为:2001