diff --git a/app/src/main/java/one/mixin/android/extension/StringExtension.kt b/app/src/main/java/one/mixin/android/extension/StringExtension.kt
index 843ec52312..dbdd0d6ce3 100644
--- a/app/src/main/java/one/mixin/android/extension/StringExtension.kt
+++ b/app/src/main/java/one/mixin/android/extension/StringExtension.kt
@@ -848,12 +848,10 @@ fun BigDecimal.currencyFormat(): String {
 
 fun String?.isValidMao(): Boolean {
     if (this.isNullOrBlank()) return false
-    val text = this.lowercase()
-    val regex = Regex("^[^\\sA-Z]{1,128}\\.mao$")
-    if (!regex.matches(text)) return false
-    val name = text.removeSuffix(".mao")
-    if (name.isBlank() || name.all { it.isDigit() }) return false
-    return true
+    val text = this.trimEnd('.').lowercase()
+    if (text.all { it.isDigit() }) return false
+    val regex = Regex("^[^\\sA-Z]{1,128}$")
+    return regex.matches(text)
 }
 
 fun String.isMao(): Boolean {
diff --git a/app/src/main/java/one/mixin/android/ui/search/SearchFragment.kt b/app/src/main/java/one/mixin/android/ui/search/SearchFragment.kt
index 483c49aa6e..5fdf572f19 100644
--- a/app/src/main/java/one/mixin/android/ui/search/SearchFragment.kt
+++ b/app/src/main/java/one/mixin/android/ui/search/SearchFragment.kt
@@ -69,7 +69,7 @@ class SearchFragment : BaseFragment(R.layout.fragment_search) {
 
     companion object {
         const val TAG = "SearchFragment"
-        const val SEARCH_DEBOUNCE = 300L
+        const val SEARCH_DEBOUNCE = 500L
     }
 
     private var keyword: String? = null
diff --git a/app/src/test/java/one/mixin/android/extension/StringExtensionTest.kt b/app/src/test/java/one/mixin/android/extension/StringExtensionTest.kt
index 2eb3d753e8..751ca9ad85 100644
--- a/app/src/test/java/one/mixin/android/extension/StringExtensionTest.kt
+++ b/app/src/test/java/one/mixin/android/extension/StringExtensionTest.kt
@@ -142,6 +142,18 @@ class StringExtensionTest {
         assertEquals("", s2.filterNonAscii())
     }
 
+    @Test
+    fun isValidMaoAllowsSearchBeforeMaoSuffix() {
+        assertTrue("alice".isValidMao())
+        assertTrue("alice.".isValidMao())
+        assertTrue("alice.mao".isValidMao())
+        assertTrue("xin.mao".isValidMao())
+        assertFalse("123".isValidMao())
+        assertFalse("has space".isValidMao())
+        assertFalse("".isValidMao())
+        assertFalse(null.isValidMao())
+    }
+
     @Test
     fun maxLimit() {
         var str =
diff --git a/app/src/test/java/one/mixin/android/ui/search/SearchFragmentTest.kt b/app/src/test/java/one/mixin/android/ui/search/SearchFragmentTest.kt
new file mode 100644
index 0000000000..34029d28bd
--- /dev/null
+++ b/app/src/test/java/one/mixin/android/ui/search/SearchFragmentTest.kt
@@ -0,0 +1,11 @@
+package one.mixin.android.ui.search
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class SearchFragmentTest {
+    @Test
+    fun searchDebounceIsHalfSecond() {
+        assertEquals(500L, SearchFragment.SEARCH_DEBOUNCE)
+    }
+}