1.Go to EC2 Dashboard and click "Running Instances" on "Security Groups"
2.select the group of your instance which you need to add security.  
3.click on the "Inbound" tab
4.Click "Edit" Button (It will open an popup window)
5.click "Add Rule"
6.Select the "Custom ICMP rule - IPv4" as Type
7.Enter the "0.0.0.0/0" as Source or your public IP

7.点击“保存”

我尝试了以上步骤中的多种解决方案，但对我有效的是

更改互联网连接到我的移动热点

再试一次。我家的网络设置不允许我连接到RDP。我在哪里可以SSH到linux服务器

转到EC2实例的安全组并编辑入站规则allow 0.0.0.0/0 for ICMP。

它会起作用的。

那些刚接触aws ec2并希望从SSH、browser、Ping从系统访问实例的人，那么下面是这些的入站规则

我有一个更深层次的问题——我已经创建了VPC、子网和适当的安全组，但忽略了添加Internet网关并将其与子网关联。因为这是我的第一个谷歌结果“不能ping ec2”，我把这个信息贴在这里，以防它被证明对别人有用(或将来我自己)。

1.Go to EC2 Dashboard and click "Running Instances" on "Security Groups"
2.select the group of your instance which you need to add security.  
3.click on the "Inbound" tab
4.Click "Edit" Button (It will open an popup window)
5.click "Add Rule"
6.Select the "Custom ICMP rule - IPv4" as Type
7.Enter the "0.0.0.0/0" as Source or your public IP

7.点击“保存”