diff --git a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java
index 2af08ec94..c42548e6a 100644
--- a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java
+++ b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java
@@ -24,6 +24,7 @@ import java.util.function.Predicate;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.web.util.UriComponentsBuilder;
 import reactor.core.publisher.Mono;
 
 import org.springframework.cloud.gateway.handler.AsyncPredicate;
@@ -176,7 +177,19 @@ public final class ServerWebExchangeUtils {
 
 	public static boolean containsEncodedParts(URI uri) {
 		boolean encoded = (uri.getRawQuery() != null && uri.getRawQuery().contains("%"))
-				|| (uri.getPath() != null && uri.getRawPath().contains("%"));
+				|| (uri.getRawPath() != null && uri.getRawPath().contains("%"));
+
+		// Verify if it is really fully encoded. Treat partial encoded as uncoded.
+		if (encoded) {
+			try {
+				UriComponentsBuilder.fromUri(uri).build(true);
+				return true;
+			} catch (IllegalArgumentException ignore) {
+			}
+
+			return false;
+		}
+
 		return encoded;
 	}
 
diff --git a/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java b/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java
index 8ff35bed7..3e420d2be 100644
--- a/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java
+++ b/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java
@@ -114,6 +114,32 @@ public class RouteToRequestUrlFilterTests {
 		assertThat(uri.getRawQuery()).isEqualTo("a=b&c=d%5B%5D");
 	}
 
+	@Test
+	public void partialEncodedParameters() {
+		URI url = UriComponentsBuilder.fromUriString(
+				"http://localhost/get?key[]=test= key&start=1533108081")
+				.build().toUri();
+
+		// prove that it is partial encoded
+		assertThat(url.getRawQuery()).isEqualTo("key[]=test=%20key&start=1533108081");
+
+		assertThat(url).hasParameter("key[]", "test= key");
+		assertThat(url).hasParameter("start", "1533108081");
+
+		MockServerHttpRequest request = MockServerHttpRequest
+				.method(HttpMethod.GET, url)
+				.build();
+
+		ServerWebExchange webExchange = testFilter(request, "http://myhost");
+		URI uri = webExchange.getRequiredAttribute(GATEWAY_REQUEST_URL_ATTR);
+		assertThat(uri).hasScheme("http").hasHost("myhost")
+				.hasParameter("key[]", "test= key")
+				.hasParameter("start", "1533108081");
+
+		// prove that it is double encoded since partial encoded uri is treated as uncoded.
+		assertThat(uri.getRawQuery()).isEqualTo("key[]=test=%2520key&start=1533108081");
+	}
+
 	@Test
 	public void encodedUrl() {
 		URI url = UriComponentsBuilder.fromUriString("http://localhost/abc def/get")