diff --git a/src/stores/index.ts b/src/stores/index.ts
index 89e3fcc26..9982dba32 100644
--- a/src/stores/index.ts
+++ b/src/stores/index.ts
@@ -43,7 +43,7 @@ export const useStore = defineStore(`store`, () => {
   // 图注格式
   const legend = useStorage(`legend`, legendOptions[3].value)
 
-  const fontSizeNumber = computed(() => fontSize.value.replace(`px`, ``))
+  const fontSizeNumber = computed(() => Number(fontSize.value.replace(`px`, ``)))
 
   // 内容编辑器编辑器
   const editor = ref<CodeMirror.EditorFromTextArea | null>(null)
@@ -132,7 +132,7 @@ export const useStore = defineStore(`store`, () => {
   const renderer = initRenderer({
     theme: customCssWithTemplate(css2json(getCurrentTab().content), primaryColor.value, customizeTheme(themeMap[theme.value], { fontSize: fontSizeNumber.value, color: primaryColor.value })),
     fonts: fontFamily.value,
-    size: fontSizeNumber.value,
+    size: fontSize.value,
   })
 
   // 更新编辑器
@@ -264,7 +264,7 @@ export const useStore = defineStore(`store`, () => {
 
   const getTheme = (size: string, color: string) => {
     const newTheme = themeMap[theme.value]
-    const fontSize = size.replace(`px`, ``)
+    const fontSize = Number(size.replace(`px`, ``))
     return customCssWithTemplate(css2json(getCurrentTab().content), color, customizeTheme(newTheme, { fontSize, color }))
   }
 
diff --git a/src/utils/index.ts b/src/utils/index.ts
index 17efcd1e8..605d5cd0d 100644
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@@ -14,7 +14,7 @@ export function addPrefix(str: string) {
 }
 
 export function customizeTheme(theme: Theme, options: {
-  fontSize?: string
+  fontSize?: number
   color?: string
 }) {
   const newTheme = JSON.parse(JSON.stringify(theme))
@@ -22,7 +22,7 @@ export function customizeTheme(theme: Theme, options: {
   if (fontSize) {
     for (let i = 1; i <= 4; i++) {
       const v = newTheme.block[`h${i}`][`font-size`]
-      newTheme.block[`h${i}`][`font-size`] = `${Number(fontSize) * Number.parseFloat(v)}px`
+      newTheme.block[`h${i}`][`font-size`] = `${fontSize * Number.parseFloat(v)}px`
     }
   }
   if (color) {