[Solved]-Highchart Donut chart not circular-Highcharts

Only one point can be sliced, so use data without the sliced property or set slicedOffset to 0.

"data": [{
    "name": "Positve",
    "y": 50,
    "color": "#2CA02C"
  },
  {
    "name": "Negative",
    "y": 25,
    "color": "#B23333"
  },
  {
    "name": "Neutral",
    "y": 25,
    "color": "#E5CF73"
  }
]

Live demo: http://jsfiddle.net/BlackLabel/1usgc4a6/

API Reference:

https://api.highcharts.com/highcharts/series.pie.data.sliced

https://api.highcharts.com/highcharts/series.pie.slicedOffset