[Solved]-Angular 8 & ChartJs change color in pie chart-Chart.js

Your issue is the form of the colors array. Instead of defining multiple backgroundColor arrays with each having one color, you should only define one array which has multiple colors. Try below and it should work:

Template

<div class="chart-wrapper">
  <canvas baseChart [data]="doughnutChartData" [labels]="doughnutChartLabels" [colors]="colors"
    [chartType]=" doughnutChartType">
  </canvas>
</div>

Controller

export class AppComponent {
  doughnutChartLabels: Label[] = ['BMW', 'Ford', 'Tesla'];

  doughnutChartData: MultiDataSet = [
    [
      55,
      25,
      20
    ]
  ];

  doughnutChartType: ChartType = 'doughnut';

  colors: Color[] = [
    {
      backgroundColor: [
        'red',
        'green',
        'blue'
      ]
    }
  ];

}