这个应该是oracle数据库编码的问题。
1 查看oracle的编码 
 select name,value$ from props$ where name like '%CHARACTER%';
NAME
--------------------------------------------------------------------------------
VALUE$
--------------------------------------------------------------------------------
NLS_NUMERIC_CHARACTERS
.,
NLS_CHARACTERSET
WE8ISO8859P1
NLS_NCHAR_CHARACTERSET
AL16UTF16
2 修改oralce的编码为UTF8
su - oracle 转换用户 
sqlplus /nolog  不连接任何数据库 
conn 用户名/密码 as sysdba 用sysdba 登陆 
shutdown immediate 关闭(shutdown Abort强行关闭) 
startup mount 启动 
alter system enable restricted session; 
alter system set job_queue_processes=0; 
alter system set aq_tm_processes=0; 
alter database open; 
alter database character set internal_use UTF8; 
ALTER DATABASE NATIONAL CHARACTER SET INTERNAL_USE UTF8;  
shutdown immediate 
startup 
 重新导入dmp文件,看看中文是否正常。