diff --git a/examples/spi_oled/Makefile b/examples/spi_oled/Makefile
index 805e3ae30ba2f8732459eceb65f1eadfa0e9dd0e..2548b289db3ebbab7dd8d1405468d13823af8d59 100644
--- a/examples/spi_oled/Makefile
+++ b/examples/spi_oled/Makefile
@@ -2,7 +2,7 @@ all : flash
 
 TARGET:=spi_oled
 
-CFLAGS+=-I../i2c_oled
+EXTRA_CFLAGS+=-I../i2c_oled
 
 include ../../ch32v003fun/ch32v003fun.mk