diff --git a/grpc.go b/grpc.go
index 9a7d98f..379c414 100644
--- a/grpc.go
+++ b/grpc.go
@@ -24,7 +24,6 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"time"
 )
 
 var (
@@ -64,7 +63,7 @@ func GRPCRequestPools(url string, business Business) (interface{}, error) {
 	)
 	if nil == pond {
 		mu.Lock()
-		pond = NewPond(10, 100, 5*time.Second, func() (conn Conn, e error) {
+		pond = NewPond(1, 10, func() (conn Conn, e error) {
 			return grpc.Dial(url, grpc.WithInsecure())
 		})
 		reqs[url] = pond
diff --git a/pool.go b/pool.go
index c9adbd1..ac88b48 100644
--- a/pool.go
+++ b/pool.go
@@ -37,10 +37,8 @@ type factory func() (Conn, error)
 //
 // maxOpen 池中最大资源数
 //
-// maxLifetime
-//
 // factory
-func NewPond(minOpen, maxOpen int, maxLifetime time.Duration, factory factory) *Pond {
+func NewPond(minOpen, maxOpen int, factory factory) *Pond {
 	if maxOpen <= 0 {
 		maxOpen = 5
 	}
@@ -48,11 +46,10 @@ func NewPond(minOpen, maxOpen int, maxLifetime time.Duration, factory factory) *
 		maxOpen = minOpen + 1
 	}
 	p := &Pond{
-		maxOpen:     maxOpen,
-		minOpen:     minOpen,
-		maxLifetime: maxLifetime,
-		factory:     factory,
-		conn:        make(chan Conn, maxOpen),
+		maxOpen: maxOpen,
+		minOpen: minOpen,
+		factory: factory,
+		conn:    make(chan Conn, maxOpen),
 	}
 
 	for i := 0; i < minOpen; i++ {
@@ -122,7 +119,11 @@ func (p *Pond) Release(conn Conn) error {
 	if p.closed {
 		return errPoolClosed
 	}
-	p.conn <- conn
+	if len(p.conn) < p.minOpen {
+		p.conn <- conn
+	} else {
+		p.Close(conn)
+	}
 	return nil
 }
 
diff --git a/pool_test.go b/pool_test.go
index b4ceec4..c36d84d 100644
--- a/pool_test.go
+++ b/pool_test.go
@@ -17,11 +17,10 @@ package gnomon
 import (
 	"google.golang.org/grpc"
 	"testing"
-	"time"
 )
 
 func TestNewPond(t *testing.T) {
-	t.Log(NewPond(10, 100, 5*time.Second, func() (conn Conn, e error) {
+	t.Log(NewPond(10, 100, func() (conn Conn, e error) {
 		return grpc.Dial("http://wwww.gnomon.com", grpc.WithInsecure())
 	}))
 }