As the @george2079 's suggetion,I post my solution from a friend as an answer,but I'm sure there are more better method can do this.I accept myself answer just for reader.If anyone have post better solution,I'll change the acceptance.

$Version

"10.3.1 for Microsoft Windows (64-bit) (December 21, 2015)"

string = First@Import["file address"];
Rule @@@ Transpose@{Keys[string], 
   URLDecode[StringReplace[Values[string], "=" -> "%"], 
    CharacterEncoding -> "UTF-8"]}

{NameLast->测试,FormattedName->测试,Phone->12345 678 9}

As the @george2079 's suggetion,I post my solution from a friend as an answer,but I'm sure there are more better method can do this.I accept myself answer just for reader.If anyone have post better solution,I'll change the acceptance.

$Version

"10.3.1 for Microsoft Windows (64-bit) (December 21, 2015)"

string = First@Import["file address"];
Rule @@@ Transpose@{Keys[string], 
   URLDecode[StringReplace[Values[string], "=" -> "%"], 
    CharacterEncoding -> "UTF-8"]}

{NameLast->测试,FormattedName->测试,Phone->12345 678 9}

As the @george2079 's suggetion,I post my solution from a friend as an answer,but I'm sure there are more better method can do this.

$Version

"10.3.1 for Microsoft Windows (64-bit) (December 21, 2015)"

string = First@Import["file address"];
Rule @@@ Transpose@{Keys[string], 
   URLDecode[StringReplace[Values[string], "=" -> "%"], 
    CharacterEncoding -> "UTF-8"]}

{NameLast->测试,FormattedName->测试,Phone->12345 678 9}

As the @george2079 's suggetion,I post my solution from a friend as an answer,but I'm sure there are more better method can do this.I accept myself answer just for reader.If anyone have post better solution,I'll change the acceptance.

$Version

"10.3.1 for Microsoft Windows (64-bit) (December 21, 2015)"

string = First@Import["file address"];
Rule @@@ Transpose@{Keys[string], 
   URLDecode[StringReplace[Values[string], "=" -> "%"], 
    CharacterEncoding -> "UTF-8"]}

{NameLast->测试,FormattedName->测试,Phone->12345 678 9}