<td><%=left(rs("field"),50)%></td>

------解决方案--------------------

给你个函数
'**************************
'函数名: Cut_String
'参  数:	s_strsrc: 字符串
'参  数:	length: 限定长度
'参  数:	points: true为有"...",false为无
'返  回: 	String
'作  用:	截断字符串
'**************************
function cut_string(byval s_strsrc, byval i_length, byval b_points)
	dim x, y, i, txt
	if trim(s_strsrc) = "" or isnull(s_strsrc) then
		cut_string = ""
		exit function
	end if
	txt = Replace(Replace(Replace(Replace(s_strsrc,"&nbsp;"," "),"&quot;",Chr(34)),"&gt;",">"),"&lt;","<")  
	x = len(txt)
	y = 0
	if x >= 1 then
		for i = 1 to x
			if asc(mid(txt, i, 1)) < 0 or asc(mid(txt, i, 1)) > 255 then '如果是汉字
				y = y + 2
			else
				y = y + 1
			end if
			
			if y >= i_length then
				if b_points then
					txt = left(txt, i) & "..." 
				else
					txt = left(txt, i)
				end if
				exit for
			end If
		next
		cut_string = txt
	else
		cut_string = ""
	end If
end function