diff --git a/product-mini/platforms/nuttx/wamr.mk b/product-mini/platforms/nuttx/wamr.mk
index 37b633131..341034e51 100644
--- a/product-mini/platforms/nuttx/wamr.mk
+++ b/product-mini/platforms/nuttx/wamr.mk
@@ -198,9 +198,7 @@ CSRCS += utils.c
 VPATH += $(IWASM_ROOT)/libraries/debug-engine
 endif
 
-ifeq ($(CONFIG_INTERPRETERS_WAMR_STACK_GUARD_SIZE),)
-CFLAGS += -DWASM_STACK_GUARD_SIZE=0
-else
+ifneq ($(CONFIG_INTERPRETERS_WAMR_STACK_GUARD_SIZE),)
 CFLAGS += -DWASM_STACK_GUARD_SIZE=CONFIG_INTERPRETERS_WAMR_STACK_GUARD_SIZE
 endif