【解决办法】调整分辨率+抗锯齿：
var viewer = new Cesium.Viewer('cesiumContainer',{
contextOptions:{
maxDrawingBufferWidth:2560*0.8,
maxDrawingBufferHeight:1600*0.8
}
});
// 是否支持图像渲染像素化处理
if (Cesium.FeatureDetection.supportsImageRenderingPixelated()) {
viewer.resolutionScale = window.devicePixelRatio
}
// 开启抗锯齿
viewer.scene.postProcessStages.fxaa.enabled = true;
