在项目根目录下找到amplify/backend/auth/yourAuthIndenittyPoolID/yourAuthIndenittyPoolID-cloudformation-template.yml文件，在Resources下添加以下内容:

YOUR_API_NAMEUnauthRole:
    Type: "AWS::IAM::Role"
    Properties:
      RoleName: "YOUR_API_NAMEUnauthRole"
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Federated:
                "cognito-identity.amazonaws.com": true
            Action:
              - "sts:AssumeRoleWithWebIdentity"
            Condition:
              StringEquals:
                "cognito-identity.amazonaws.com:aud":
                  "YOUR_AUTH_IDENTITY_POOL_ID"
              "ForAnyValue:StringLike":
                "cognito-identity.amazonaws.com:amr":
                  "unauthenticated"
      Path: "/"
      Policies:
        - PolicyName: "YOUR_API_NAMEUnauthRolePolicy"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: "Allow"
                Action:
                  - "execute-api:Invoke"
                Resource:
                  - "arn:aws:execute-api:YOUR_REGION:YOUR_ACCOUNT_ID:YOUR_API_GATEWAY_ID/*/*/*"
YOUR_API_NAMEAuthRole:
    Type: "AWS::IAM::Role"
    Properties:
      RoleName: "YOUR_API_NAMEAuthRole"
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Federated:
                "cognito-identity.amazonaws.com": true
            Action:
              - "sts:AssumeRoleWithWebIdentity"
            Condition:
              StringEquals:
                "cognito-identity.amazonaws.com:aud":
                  "YOUR_AUTH_IDENTITY_POOL_ID"
              "ForAnyValue:StringLike":
                "cognito-identity.amazonaws.com:amr":
                  "authenticated"
      Path: "/"
      Policies:
        - PolicyName: "YOUR_API_NAMEAuthRolePolicy"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: "Allow"
                Action:
                  - "execute-api:Invoke"
                Resource:
                  - "arn:aws:execute-api:YOUR_REGION:YOUR_ACCOUNT_ID:YOUR_API_GATEWAY_ID/*/*/*"

其中，YOUR_API_NAME、YOUR_REGION、YOUR_ACCOUNT_ID、YOUR_API_GATEWAY_ID、YOUR_AUTH_IDENTITY_POOL_ID需要替换成您自己的信息。

然后再运行'amplify push”命令，即可成功部署