DATA  SEGMENT
       COUNT  EQU       10
         NUM  DB        10 DUP(?)
        IBUF  DB        7,0,6 DUP(?)
        OBUF  DB        6  DUP(?)
      INFOR1  DB        "PLEASE INPUT 10 NUMBERS:",0AH,0DH,'$'
      INFOR2  DB        "THE MAX  FOUND IN THE 10 NUMBERS IS $"
      INFOR3  DB        0AH,0DH,'$'
        DATA  ENDS
       STACK  SEGMENT   STACK
       DATA2  DW        40  DUP(?)
         TOP  EQU       LENGTH DATA2
       STACK  ENDS
        CODE  SEGMENT
              ASSUME    CS:CODE,DS:DATA,SS:STACK
      START:  MOV       AX,DATA
              MOV       DS,AX
              MOV       AX,STACK
              MOV       SS,AX
              MOV       AX,TOP
              MOV       SP,AX

用emu8086编译的时候总是报错，为什么呢？

什么错？

wrong parameters:mov ax,length data2
probably no zero prefix fof hex;or no 'h' suffix;or wrong address;or underfined var;length data2

那可能是不支持

记住 length 是伪指令 至于嘛是伪指令 百度去罢