1、去http://www.oracle.com/technetwork/database/features/instant-client/index-097480.html下载Instant Client Package - Basic: All files required to run OCI, OCCI, and JDBC-OCI applications

instantclient-basic-win-x86-64-11.2.0.1.0.zip (55,084,309 bytes)

2、将下载的客户端包安装到例如E:\App\PLSQL下，最终客户端主目录是E:\App\PLSQL\instantclient_11_2

3、设定环境变量

NLS_LANG = SIMPLIFIED CHINESE_CHINA.ZHS16GBK

TNS_ADMIN = E:\App\PLSQL\instantclient_11_2

4、配置PL/SQL Developer 环境设置（打开PL/SQL，取消登录，直接配置），  在”工具 -> 首选项 -> 连接“下设置：

Oracle主目录名  = E:\App\PLSQL\instantclient_11_2

OCI库 = E:\App\PLSQL\instantclient_11_2\oci.dll

5、从C:\oraclexe\app\oracle\product\11.2.0\server\network\ADMIN下拷贝文件tnsnames.ora到E:\App\PLSQL\instantclient_11_2下，

并配置E:\App\PLSQL\instantclient_11_2\tnsnames.ora

XE =
       (DESCRIPTION =
         (ADDRESS_LIST =
           (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
         )
         (CONNECT_DATA =
           (SERVER = DEDICATED)
           (SERVICE_NAME = XE)
         )
       )

smis =
        (DESCRIPTION =
          (ADDRESS_LIST =
            (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.75.61)(PORT = 1521))
          )
          (CONNECT_DATA =
            (SERVICE_NAME = orcl)
          )
        )

6、打开PL/SQL测试OracleXE连接成功。