diff --git a/build/android/make-Android.bash b/build/android/make-Android.bash
index 1277810b..d0f8095b 100755
--- a/build/android/make-Android.bash
+++ b/build/android/make-Android.bash
@@ -8,7 +8,7 @@ cmake -DCMAKE_TOOLCHAIN_FILE=./android.toolchain.cmake                      \
       -DANDROID_SYSROOT=${PLATFORM}                                         \
       -DANDROID_ABI="armeabi-v7a with NEON"                                 \
       -DANDROID_TOOLCHAIN_NAME="arm-linux-androideabi-4.8"                  \
-      -DANDROID_NATIVE_API_LEVEL=android-17                                 \
+      -DANDROID_NATIVE_API_LEVEL=android-21                                 \
       -DANDROID_STL=none                                                    \
       ../../
 
diff --git a/osal/android/os_env.c b/osal/android/os_env.c
new file mode 100644
index 00000000..0ab1e55e
--- /dev/null
+++ b/osal/android/os_env.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2010 Rockchip Electronics S.LSI Co. LTD
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include "os_env.h"
+#include <sys/system_properties.h>
+
+/*
+ * NOTE: __system_property_set only available after android-21
+ * So the library should compiled on latest ndk
+ */
+
+RK_S32 os_get_env_u32(const char *name, RK_U32 *val)
+{
+    RK_S32 ret = -1;
+    char value[PROP_VALUE_MAX+1];
+    int len = __system_property_get(name, value);
+    *val = 0;
+    if (len > 0) {
+        char *endptr;
+        int base = (value[0] == '0' && value[1] == 'x')?(16):(10);
+        errno = 0;
+        *val = strtoul(value, &endptr, base);
+        if (errno || (value == endptr)) {
+            errno = 0;
+        } else {
+            ret = 0;
+        }
+    }
+    return ret;
+}
+
+RK_S32 os_get_env_str(const char *name, char **val)
+{
+    // use unsigned char to avoid warnning
+    static unsigned char env_str[2][PROP_VALUE_MAX+1];
+    static RK_U32 env_idx = 0;
+    char *value = (char *)env_str[env_idx];
+    int len = __system_property_get(name, value);
+    *val = (len)?(value):(NULL);
+    env_idx = (len)?(!env_idx):(env_idx);
+    return (len)?(0):(-1);
+}
+
+RK_S32 os_set_env_u32(const char *name, RK_U32 val)
+{
+    char buf[PROP_VALUE_MAX+1+2];
+    snprintf(buf, sizeof(buf), "0x%x", val);
+    int len = __system_property_set(name, buf);
+    return (len)?(0):(-1);
+}
+
+RK_S32 os_set_env_str(const char *name, char *val)
+{
+    int len = __system_property_set(name, val);
+    return (len)?(0):(-1);
+}
+
+