改用
<div [ngStyle]="{background: 'url(/img/' + item.img + ')', width: '200px', height: '150px'"></div>要么
<div [style.background]="'url(/img/' + item.img + ')'" [style.width.px]="200" [style.height.px]="150p"></div>

改用
<div [ngStyle]="{background: 'url(/img/' + item.img + ')', width: '200px', height: '150px'"></div>要么
<div [style.background]="'url(/img/' + item.img + ')'" [style.width.px]="200" [style.height.px]="150p"></div>