我建议使用setInterval而不是setTimeout。

这是一些代码，使用您提供的JSON并通过为每个标记添加必需的“
description”成员，在小提琴中通过JSON模拟更新：

var map = null;
var gmarkers = [];
var intervalNumber = 0;
setInterval(function () {
    new Request.JSON({
        url: '/echo/json/',
        data: {
            json: JSON.encode([{
                "lat": 35.6606376 + (0.01 * intervalNumber),
                    "lng": -80.5048653 + (0.1 * intervalNumber),
                    "content": "bca",
                "description":"first marker"
            }, {
                "lat": 42.6799504 + (0.01 * intervalNumber),
                    "lng": -36.4949205 - (0.1 * intervalNumber),
                    "content": "abc",
                "description": "second marker"
            }]),
            delay: 3
        },
        onSuccess: function (response) {
            update_map(response);
            intervalNumber++;
        }
    }).send();
}, 5000);
update_map = function (data) {
    var bounds = new google.maps.LatLngBounds();

    // delete all existing markers first
    for (var i = 0; i < gmarkers.length; i++) {
        gmarkers[i].setMap(null);
    }
    gmarkers = [];

    // add new markers from the JSON data
    for (var i = 0, length = data.length; i < length; i++) {
        latLng = new google.maps.LatLng(data[i].lat, data[i].lng);
        bounds.extend(latLng);
        var marker = new google.maps.Marker({
            position: latLng,
            map: map,
            title: data[i].title
        });
        var infoWindow = new google.maps.InfoWindow();
        google.maps.event.addListener(marker, "click", function (e) {
            infoWindow.setContent(data.description+"<br>"+marker.getPosition().toUrlValue(6));
            infoWindow.open(map, marker);
        });
        (function (marker, data) {
            google.maps.event.addListener(marker, "click", function (e) {
                infoWindow.setContent(data.description+"<br>"+marker.getPosition().toUrlValue(6));
                infoWindow.open(map, marker);
            });
        })(marker, data[i]);
        gmarkers.push(marker);
    }

    // zoom the map to show all the markers, may not be desirable.
    map.fitBounds(bounds);
};

function initialize() {
    // initialize the map on page load.
    var mapOptions = {
        center: new google.maps.LatLng(35.66, -80.50),
        zoom: 8,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    map = new google.maps.Map(document.getElementById("map-canvas"),
    mapOptions);

    // add the markers to the map if they have been loaded already.
    if (gmarkers.length > 0) {
        for (var i = 0; i < gmarkers.length; i++) {
            gmarkers[i].setMap(map);
        }
    }
}

google.maps.event.addDomListener(window, 'load', initialize);