分析:据绝对值的定义,由已知a=1999,可得|3a3-2a2+4a-1|=3a3-2a2+4a-1,|3a3-3a2+3a-2001|=3a3-3a2+3a-2001,去掉绝对值化简即可.
解答:解:当a=1999时,|3a3-2a2+4a-1|=3a3-2a2+4a-1,|3a3-3a2+3a-2001|=3a3-3a2+3a-2001,
∴原式=3a3-2a2+4a-1-(3a3-3a2+3a-2001)
=a2+a+2000
=a(a+1)+2000
=1999×2000+2000
=2000×(1999+1)
=4000000.
点评:本题考查绝对值的化简,正数的绝对值等于它本身,0的绝对值是0,负数的绝对值为其相反数.
熟练掌握该知识点是解答本题的关键.