diff --git a/util/logs/workflow-logger.go b/util/logs/workflow-logger.go
index 2cc93acfe2f6..753f378082e2 100644
--- a/util/logs/workflow-logger.go
+++ b/util/logs/workflow-logger.go
@@ -41,6 +41,27 @@ type sender interface {
 	Send(entry *workflowpkg.LogEntry) error
 }
 
+const maxTokenLength = 1024 * 1024
+const startBufSize = 16 * 1024
+
+func scanLinesOrGiveLong(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	advance, token, err = bufio.ScanLines(data, atEOF)
+	if advance > 0 || token != nil || err != nil {
+		// bufio.ScanLines found something, use it
+		return
+	}
+
+	// bufio.ScanLines found nothing
+	// if our buffer is still a reasonable size, continue scanning for regular lines
+	if len(data) < maxTokenLength {
+		return
+	}
+
+	// our buffer is getting massive, stop waiting for line breaks and return data now
+	// this avoids bufio.ErrTooLong
+	return maxTokenLength, data[0:maxTokenLength], nil
+}
+
 func WorkflowLogs(ctx context.Context, wfClient versioned.Interface, kubeClient kubernetes.Interface, req request, sender sender) error {
 	wfInterface := wfClient.ArgoprojV1alpha1().Workflows(req.GetNamespace())
 	_, err := wfInterface.Get(ctx, req.GetName(), metav1.GetOptions{})
@@ -111,7 +132,12 @@ func WorkflowLogs(ctx context.Context, wfClient versioned.Interface, kubeClient
 					logCtx.Error(err)
 					return
 				}
+
 				scanner := bufio.NewScanner(stream)
+				//give it more space for long line
+				scanner.Buffer(make([]byte, startBufSize), maxTokenLength)
+				//avoid bufio.ErrTooLong error when encounters a very very long line
+				scanner.Split(scanLinesOrGiveLong)
 				for scanner.Scan() {
 					select {
 					case <-ctx.Done():
@@ -119,7 +145,11 @@ func WorkflowLogs(ctx context.Context, wfClient versioned.Interface, kubeClient
 					default:
 						line := scanner.Text()
 						parts := strings.SplitN(line, " ", 2)
-						content := parts[1]
+						//on old version k8s, the line may contains no space, hence len(parts) would equal to 1
+						content := ""
+						if len(parts) > 1 {
+							content = parts[1]
+						}
 						timestamp, err := time.Parse(time.RFC3339, parts[0])
 						if err != nil {
 							logCtx.Errorf("unable to decode or infer timestamp from log line: %s", err)